201209471 六、發明說明： 【發明所屬之技術領域】 本發明是有關於一種光學鏡頭，且特別是有關於一種可 應用於投影系統以及取像系統的成像鏡頭。 【先前技術】 一高品質的鏡頭模組需具備低畸變像差、高解析度、高 對比度、尚照度均勻性等特性。除了高品質畫面的需求外， 例如在投影系統中為了於小空間中投影一大畫面，或者在取 像系統中為取得大範圍的影像，往往需要一大的視場角，但 大的視場角容易提高畸變像差。再者，為增加光線的利用率 和畫面照度的均勻性，會要求鏡頭系統其縮小側的主光線相 對光軸的最大角度(遠心角）要盡可能地小，使主光線和光轴 能接近平行。上述各個要求往往相互衝突，而增加鏡頭設計 的困難度，例如鏡頭的畸變像差必須儘可能地小，但如此會 導致無法提面鏡頭的視場角並使鏡片數量增加；若鏡頭具有 較大的視場角且縮小側的主光線和光軸接近平行，則鏡頭 的長度和鏡片尺寸就容易變大，無法逹到小尺寸的目的。 美國專利US6674582揭露一種顯微鏡變焦物鏡系統，其 201209471 包括具有正折射光焦度的第一透鏡群、具有負折射光焦度的 第二透鏡群以及具有正折射光焦度的第三透鏡群。美國專利 US5600490揭露一種變焦鏡頭，其自螢幕端依序為正折射光 焦度的第一透鏡群、負折射光焦度的第二透鏡群及正折射光 焦度的第三透鏡群。此外，美國專利US7342723揭露一種廣 角才又影鏡頭，其自螢幕端依序為負折射光焦度的第一透鏡 群、負折射光焦度的第二透鏡群及正折射光焦度的第三透鏡 群。 综合上述，為了達到小尺寸、減少鏡片數及遠心鏡頭的 要求，鏡片通常需具備較大的屈光度，但這會使鏡頭產生較 大的像差而降低影像品質。另外，一般要達到高成像品質、 低畸變像差、高解析度、高對比度和高畫面照度均勻性等眾 多需求’一般而言會使用到9片以上的玻璃球面鏡片，如此 鏡頭體積會變大且長度較長，無法達到降低成本和小型化的 【發明内容】 本發明提供一種鏡頭模組，具有縮短鏡頭長度，減少鏡 片數以縮小鏡頭體積而達到成本降低以及獲得高成像品 質、低畴變像差、高解析度、高對比度和高畫面照度的需求。 201209471 本發明的其他目的和優點可以從本發明所揭露的技術 特徵中得到進一步的了解。 為達上述之-或部份或全部目的或是其他目的本發明 之一實施例提供一種鏡頭模組，包含—第一透鏡群、一第 二透鏡群及-第三透鏡群。第—透鏡群具有正屈光度且 基本上由從一放大側至一縮小侧依序排列的一第一透 鏡、一第二透鏡以及一第三透鏡所組成，且第一透鏡、 第二透鏡以及第三透鏡的屈光度依序為負、正、正。第 二透鏡群具有負屈光度且配置於第一透鏡群與縮小側之 間’第二透鏡群基本上由從放大側至縮小侧依序排列的 —第四透鏡及一第五透鏡所組成，第四透鏡的屈光度為 負且第五透鏡的屈光度為正。第三透鏡群具有正屈光度 且配置於第二透鏡群與縮小側之間，第三透鏡群基本上 由從放大侧至縮小側依序排列的一第六透鏡及一第七透 鏡所組成，該第六透鏡的屈光度為正且該七透鏡的屈光 度為正。 本發明之另一實施例提供一種鏡頭模組，包含一第一 透鏡群、一第二透鏡群及一第三透鏡群。第一透鏡群具 有正屈光度且基本上由從一放大側至一縮小側依序排列 的—第一透鏡、一第二透鏡以及一第三透鏡所組成，且 第一透鏡、第二透鏡以及第三透鏡的屈光度依序為負、 正、正。第二透鏡群配置於第一透鏡群與縮小側之間且 201209471 包含一第四透鏡，該第四透鏡的屈光度為負。第三透鏡 群具有正屈光度且配置於第二透鏡群與縮小側之間，第 二透鏡群基本上由從放大側至縮小側依序排列的一第五 透鏡及一第六透鏡所組成，第五透鏡的屈光度為正且第 六透鏡的屈光度為正。 於一實施例中，鏡頭模組更包含一孔徑光攔設置於第 一透鏡群與第二透鏡群之間，其中第一透鏡群、孔徑光 欄與第二透鏡群為連動的對焦群，而第三透鏡群為一固 定群。 於一實施例中，第一透鏡構成第一透鏡群的一第一 子群，第二透鏡連同第三透鏡構成第一透鏡群的一第二 子群，鏡頭模組之有效焦距為f，第二子群的有效焦距為 fsG2，且鏡頭模組滿足下列條件： 0.2<fSG2/f<0.5。 於一實施例中’鏡頭模組之有效焦距為f，第二透鏡 群的有效焦距為fG2 ’且鏡頭模組滿足下列條件： 〇.6< I fG2 | / f< L5。 於一實施例中，第三透鏡的阿貝數為2；3,第四透鏡 的阿貝數為’且鏡頭模組滿足下列條件： 20<]^3 ~" 1^4<37。 於一實施例中，鏡頭模組之有效焦距為f，第二透鏡 群中最靠近縮小側的透鏡表面的中心至第三透鏡群最靠 201209471 近放大側的透鏡表面的中叫距離為Lg2g 滿足下列條件： 0.4 < Lg2-G3〆 f < 1 〇 於一實施射，鏡賴組之有效焦距為 群的有效焦距為fG3，且鏡頭模組滿足下列條件·一兄 〇.6<fG3/f<2。 · 藉由上述各個實施狀設計，鏡賴㈣有如下全 部或至少其一之優點： (1) 低橫向色差； (2) 低畸變像差； (3) 大視場角； (4) 低遠心角，可控制在3.1度内；及 (5) 僅使用6片鏡片即可達到修正像差的目的。 $明的其他目的和優點可以從本發明所揭露的技術 心賴進-步的了解。為讓本發明之上述和其他目的、 ★徵和優點能更明顯易懂，下文特舉實施例並配合所附圖 巧，作詳細說明如下。 【實施方式】 有關本發明讀述及其他技_容、_與功效，在以 己口參考圖式之一較佳實施例的詳細說明中，將可清楚的 201209471 呈現。以下實施例中提到的方向用語，例如「上」、「下」、 「前」、「後」、「左」、「右」等，僅是參考附加圖式的方 向。因此，使用的方向用語是用來說明並非用來限制本 發明。 圖1為依本發明一實施例之鏡頭模組1〇的示意圖， 鏡頭模組10設置於一放大側與一縮小側之間，縮小侧可 設置有一影像處理元件40,且影像處理元件40舉例而言 可為電荷麵合元件(charge coupled device，CCD)影像感測 器或互補性氧化金屬半導體(complementary metal-oxide semiconductor，CMOS)影像感測器等感光元件，或是為 數位微鏡元件(digital micro-mirror device，DMD)、梦基 液晶面板（liquid-crystal-on-silicon panel，LCOS panel)或 穿透式液晶面板(transmissive liquid crystal panel， transmissive LCD)等光閥(light valve)。如圖 1 所示，鏡頭 模組10包含具正屈光度的一第一透鏡群12、具負屈光度 的一第二透鏡群14以及具正屈光度的一第三透鏡群16， 第一透鏡群12鄰近放大側，第三透鏡群16鄰近縮小側， 且第二透鏡群14位於第一透鏡群12與第三透鏡群16之 間。第一透鏡群12包含從放大側至縮小側依序排列的一 第一透鏡L1、一第二透鏡L2及一第三透鏡L3，第二透 鏡群14包含從放大側至縮小側依序排列的一第四透鏡 L4及一第五透鏡L5，第三透鏡群16包含從放大側至縮201209471 VI. Description of the Invention: [Technical Field] The present invention relates to an optical lens, and more particularly to an imaging lens applicable to a projection system and an image taking system. [Prior Art] A high-quality lens module needs to have low distortion aberration, high resolution, high contrast, and uniform illumination. In addition to the need for high-quality images, for example, in projection systems, in order to project a large picture in a small space, or in a retrieval system to obtain a wide range of images, a large field of view is often required, but a large field of view The angle is easy to increase the distortion aberration. Furthermore, in order to increase the utilization of light and the uniformity of the illumination of the screen, it is required that the maximum angle (telecentric angle) of the principal ray of the lens system on the reduced side relative to the optical axis should be as small as possible so that the chief ray and the optical axis can be nearly parallel. . The above requirements often conflict with each other, and the difficulty of increasing the lens design, for example, the distortion of the lens must be as small as possible, but this will result in the angle of view of the lens being unable to be raised and the number of lenses being increased; The angle of view and the main ray and the optical axis of the reduced side are nearly parallel, and the length of the lens and the size of the lens are easily enlarged, so that the small size cannot be achieved. U.S. Patent 6,674,582 discloses a microscope zoom objective system, which 201209471 includes a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power. U.S. Patent No. 5,600,490 discloses a zoom lens which, in order from the screen, is a first lens group of positive refractive power, a second lens group of negative refractive power, and a third lens group of positive refractive power. In addition, U.S. Patent No. 7,342,723 discloses a wide-angle reshaping lens in which a first lens group of negative refractive power, a second lens group of negative refractive power, and a third of positive refractive power are sequentially ordered from the screen end. Lens group. In summary, in order to achieve a small size, a reduction in the number of lenses, and a telecentric lens, the lens usually needs to have a large refracting power, but this causes a large aberration of the lens to reduce image quality. In addition, it is generally required to achieve high image quality, low distortion aberration, high resolution, high contrast and high image illumination uniformity. In general, more than 9 glass spherical lenses will be used, so that the lens volume will become larger. The invention has a lens module which has the advantages of shortening the length of the lens, reducing the number of lenses to reduce the volume of the lens, achieving cost reduction, and obtaining high image quality and low domain variation. Aberration, high resolution, high contrast and high screen illumination requirements. 201209471 Other objects and advantages of the present invention will be further understood from the technical features disclosed herein. An embodiment of the present invention provides a lens module including a first lens group, a second lens group, and a third lens group in order to achieve the above-mentioned or some or all of the objectives or other objects. The first lens group has a positive refracting power and is basically composed of a first lens, a second lens and a third lens which are sequentially arranged from an enlarged side to a reduced side, and the first lens, the second lens and the first lens The diopter of the three lenses is negative, positive, and positive. The second lens group has a negative refracting power and is disposed between the first lens group and the reduction side. The second lens group is basically composed of a fourth lens and a fifth lens arranged in order from the magnification side to the reduction side. The diopter of the four lenses is negative and the diopter of the fifth lens is positive. The third lens group has a positive refractive power and is disposed between the second lens group and the reduction side, and the third lens group is basically composed of a sixth lens and a seventh lens which are sequentially arranged from the magnification side to the reduction side. The diopter of the sixth lens is positive and the refracting power of the seven lenses is positive. Another embodiment of the present invention provides a lens module including a first lens group, a second lens group, and a third lens group. The first lens group has a positive refracting power and is basically composed of a first lens, a second lens and a third lens which are sequentially arranged from an enlarged side to a reduced side, and the first lens, the second lens and the first lens The diopter of the three lenses is negative, positive, and positive. The second lens group is disposed between the first lens group and the reduction side and 201209471 includes a fourth lens having a negative diopter. The third lens group has a positive refractive power and is disposed between the second lens group and the reduction side, and the second lens group is basically composed of a fifth lens and a sixth lens arranged in order from the magnification side to the reduction side, The diopter of the fifth lens is positive and the diopter of the sixth lens is positive. In an embodiment, the lens module further includes an aperture stop disposed between the first lens group and the second lens group, wherein the first lens group, the aperture stop, and the second lens group are linked groups, and The third lens group is a fixed group. In one embodiment, the first lens constitutes a first subgroup of the first lens group, and the second lens together with the third lens constitutes a second subgroup of the first lens group, and the effective focal length of the lens module is f, The effective focal length of the two subgroups is fsG2, and the lens module satisfies the following conditions: 0.2 < fSG2 / f < 0.5. In an embodiment, the effective focal length of the lens module is f, the effective focal length of the second lens group is fG2 ' and the lens module satisfies the following conditions: 〇.6< I fG2 | / f< L5. In one embodiment, the third lens has an Abbe number of 2; 3, and the fourth lens has an Abbe number of ' and the lens module satisfies the following condition: 20<]^3 ~"1^4<37. In one embodiment, the effective focal length of the lens module is f, the center of the lens surface closest to the reduction side of the second lens group to the lens lens surface of the third lens group closest to 201209471 near the magnification side is Lg2g satisfied. The following conditions: 0.4 < Lg2-G3〆f < 1 〇 In one implementation, the effective focal length of the mirror group is fG3, and the lens module satisfies the following conditions: one brother.6<fG3/ f<2. · With the above embodiments, the mirror (4) has all or at least one of the following advantages: (1) low lateral chromatic aberration; (2) low distortion aberration; (3) large angle of view; (4) low telecentricity The angle can be controlled within 3.1 degrees; and (5) the correction aberration can be achieved by using only 6 lenses. Other purposes and advantages of the invention can be understood from the teachings of the present invention. The above and other objects, features and advantages of the present invention will become more apparent and understood. [Embodiment] The detailed description of the preferred embodiment of the present invention will be apparent from the detailed description of the preferred embodiment of the present invention. The directional terms mentioned in the following embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only directions in which the additional drawings are referred. Therefore, the directional terminology used is for the purpose of illustration and not limitation. 1 is a schematic diagram of a lens module 1 according to an embodiment of the present invention. The lens module 10 is disposed between an enlarged side and a reduced side, and an image processing component 40 is disposed on the reduced side, and the image processing component 40 is illustrated by way of example. For example, it may be a charge coupled device (CCD) image sensor or a complementary metal-oxide semiconductor (CMOS) image sensor or the like, or a digital micromirror device ( A light valve such as a digital micro-mirror device (DMD), a liquid-crystal-on-silicon panel (LCOS panel), or a transmissive liquid crystal panel (transmissive LCD). As shown in FIG. 1, the lens module 10 includes a first lens group 12 having positive refracting power, a second lens group 14 having negative refracting power, and a third lens group 16 having positive refracting power. The first lens group 12 is adjacent to each other. On the magnification side, the third lens group 16 is adjacent to the reduction side, and the second lens group 14 is located between the first lens group 12 and the third lens group 16. The first lens group 12 includes a first lens L1, a second lens L2, and a third lens L3 arranged in order from the magnification side to the reduction side, and the second lens group 14 is sequentially arranged from the magnification side to the reduction side. a fourth lens L4 and a fifth lens L5, the third lens group 16 including from the magnification side to the contraction
LSI 9 201209471 小側依序排列的一第六透鏡L6及一第七透鏡L7。第一 透鏡L1、第一透鏡L2、第三透鏡L3、第四透鏡L4、第 五透鏡L5、第六透鏡L6與第七透鏡L7的屈光度依序為 負、正、正、負、正、正、正。在本實施例中，第一透 鏡L1的凹面朝向縮小側，第二透鏡L2的凸面朝向縮小 側，第三透鏡L3的凸面朝向放大側，第四透鏡L4的凹 面朝向縮小側，第五透鏡L5的凸面朝向縮小側，且第六 透鏡L6與第七透鏡L7的凸面均朝向縮小側。再者，鏡 頭模組10可包含一孔徑光攔(aperture st〇p)18設置於第_ 透鏡群12與第二透鏡群14之間。第一透鏡群、孔徑 光攔18與第二透鏡群14為連動的對焦群，而第三透鏡 群16為固定群。於本實施例中，鏡頭模組1〇包含非球 面鏡片以減少鏡片數，舉例而言，習知一有效焦距為 10mm的鏡頭系統，大約需使用8_9片鏡片，但若使用 非球面鏡片，鏡片數可減少至6_7片鏡片，如此可減少 鏡頭系統的長度，且因非球面鏡片可採用塑膠材質，進 而可降低製造成本。再者，為達到廣角化的目的，本實 施例設計使第一透鏡L1的屈光度為負。另外，為了修正 第一透鏡L1的負屈光度所產生的像差，第二透鏡^2及 第二透鏡L3需有較大的正屈光度。另外，為有效減少畸 變(distortion)同時獲得遠心(teiecentrjc)鏡頭系統的效 果，第二透鏡群16需包含兩片正透鏡，即第六透鏡L6 201209471 與第七透鏡L7的屈光度均需為正。 如下說明圖1之鏡頭模組10的一透鏡設計實例。需 注意下述之表一及表二中所列的設計值並非用以限定本 發明’任何熟習此項技術之人士在參照本發明之後，當 可對其參數或設定作適當更動，惟其仍屬於本發明之範 嘴内。 [S] <表一 > ----— 表面 曲率半徑 (mm) 間距(mm) 折射率 阿貝數 S1 —----| -341.635843 0.750000 1.707979 50.2746 S2 ------_ 5.664991 0.576041 S3 17.346865 1.335434 1.89303 31.3339 S4 -15.284495 0.154126 S5 4.492318 1.469950 1.882997 40.7651 S6 -90.177079 0.028946 孔徑光 欄(S7) Infiiity 0.384792 S8 -39.098123 0.750000 1.92286 18.8969 S9 4.040811 0.990438 S10 — ---- 一 -4.852605 1.236205 1.826774 43.6074 11 201209471 S11 -3.308809 5.657070 S12 -19.854730 1.683904 1.834 37.2 S13 -11.665049 0.100000 S14 -27.739016 1.714693 1.834 37.2 S15 -13.000000 0.100000 S16 Infinity 0.400000 1.508469 61.1878 S17 Infinity 0.306000 IMA Infinity 0A sixth lens L6 and a seventh lens L7 are arranged in sequence on the small side of the LSI 9 201209471. The diopter of the first lens L1, the first lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are negative, positive, positive, negative, positive, positive. ,positive. In the present embodiment, the concave surface of the first lens L1 faces the reduction side, the convex surface of the second lens L2 faces the reduction side, the convex surface of the third lens L3 faces the magnification side, the concave surface of the fourth lens L4 faces the reduction side, and the fifth lens L5 The convex surface faces the reduction side, and the convex surfaces of the sixth lens L6 and the seventh lens L7 both face the reduction side. Furthermore, the lens module 10 can include an aperture stop 18 disposed between the _ lens group 12 and the second lens group 14. The first lens group, the aperture stop 18 and the second lens group 14 are interlocking focus groups, and the third lens group 16 is a fixed group. In this embodiment, the lens module 1 includes an aspherical lens to reduce the number of lenses. For example, a lens system with an effective focal length of 10 mm requires about 8 to 9 lenses, but if an aspherical lens is used, The number of lenses can be reduced to 6_7 lenses, which can reduce the length of the lens system, and the aspherical lens can be made of plastic material, which can reduce the manufacturing cost. Further, in order to achieve wide angle, the present embodiment is designed such that the diopter of the first lens L1 is negative. Further, in order to correct the aberration caused by the negative refracting power of the first lens L1, the second lens 2 and the second lens L3 need to have a large positive refracting power. In addition, in order to effectively reduce the distortion and at the same time obtain the effect of the telecentric lens system, the second lens group 16 needs to include two positive lenses, that is, the diopter of the sixth lens L6 201209471 and the seventh lens L7 needs to be positive. A lens design example of the lens module 10 of FIG. 1 is explained as follows. It should be noted that the design values listed in Tables 1 and 2 below are not intended to limit the present invention. Anyone skilled in the art will be able to make appropriate changes to their parameters or settings after referring to the present invention, but still belong to Within the scope of the invention. [S] <Table 1> ----- Surface Curvature Radius (mm) Spacing (mm) Refractive Index Abbe Number S1 —----| -341.635843 0.750000 1.707979 50.2746 S2 ------_ 5.664991 0.576041 S3 17.346865 1.335434 1.89303 31.3339 S4 -15.284495 0.154126 S5 4.492318 1.469950 1.882997 40.7651 S6 -90.177079 0.028946 Aperture diaphragm (S7) Infiiity 0.384792 S8 -39.098123 0.750000 1.92286 18.8969 S9 4.040811 0.990438 S10 — ---- A-4.852605 1.236205 1.826774 43.6074 11 201209471 S11 -3.308809 5.657070 S12 -19.854730 1.683904 1.834 37.2 S13 -11.665049 0.100000 S14 -27.739016 1.714693 1.834 37.2 S15 -13.000000 0.100000 S16 Infinity 0.400000 1.508469 61.1878 S17 Infinity 0.306000 IMA Infinity 0
在表一中，間距是指兩相鄰表面間於光轴A上之直 線距離，舉例來說，表面S1之間距，即表面S1至表面 S2於光轴A上之直線距離。此外，在表一中，表面S1、 S2為第一透鏡L1的兩表面，表面S3、S4為第二透鏡L2 的兩表面，表面S5、S6為第三透鏡L3的兩表面，表面 S7為孔徑光欄18,表面S8、S9為第四透鏡L4的兩表面， 表面S10、S11為第五透鏡L5的兩表面，表面S12、S13 為第六透鏡L6的兩表面，表面S14、S15為第七透鏡L7 的兩表面，且表面S16、S17為一用於影像處理元件40 之玻璃蓋(cover glass) 22的兩表面，再者，於本設計例中 第五透鏡L5使用非球面鏡片，即表面S10、S11為非球 面，而非球面的公式如下： [S1 12 201209471 Z(h)=WwTTk)hv + Czh2+ah4+C6h6+Qh8+Cl0h，°+c-2h，2 於上式中，z為光軸方向之偏移量（sag)，h為非球 面上距光軸的垂直高度，r為接近光軸處的曲率半徑，k 是二次曲面常數(conic constant)，而C2-C12為非球面高次項 係數(aspheric coefficient)。表面S10、S11的非球面係數及k 值如表二所示··In Table 1, the pitch refers to the linear distance between two adjacent surfaces on the optical axis A. For example, the distance between the surfaces S1, that is, the linear distance from the surface S1 to the surface S2 on the optical axis A. Further, in Table 1, the surfaces S1, S2 are the two surfaces of the first lens L1, the surfaces S3, S4 are the two surfaces of the second lens L2, the surfaces S5, S6 are the two surfaces of the third lens L3, and the surface S7 is the aperture In the diaphragm 18, the surfaces S8 and S9 are the two surfaces of the fourth lens L4, the surfaces S10 and S11 are the surfaces of the fifth lens L5, the surfaces S12 and S13 are the surfaces of the sixth lens L6, and the surfaces S14 and S15 are the seventh. Both surfaces of the lens L7, and the surfaces S16, S17 are two surfaces of a cover glass 22 for the image processing element 40. Further, in the present design example, the fifth lens L5 uses an aspherical lens, that is, a surface. S10 and S11 are aspherical, and the formula of the non-spherical surface is as follows: [S1 12 201209471 Z(h)=WwTTk)hv + Czh2+ah4+C6h6+Qh8+Cl0h,°+c-2h,2 In the above formula, z The offset of the optical axis direction (sag), h is the vertical height from the optical axis on the aspherical surface, r is the radius of curvature near the optical axis, k is the conic constant, and C2-C12 is Aspherical coefficient of asphericity. The aspherical coefficients and k values of the surfaces S10 and S11 are as shown in Table 2.
〈表二> S10 Sll K 0 0 C2= 0 0 C4= -7.65E-03 -2.21E-03 C6= 1.33E-03 3.84E-04 C8= -1.77E-03 -3.74E-04 C10= 5.49E-04 7.85E-05 C12= -8.38E-05 -8.65E-06 圖2為依本發明另一實施例之鏡頭模組30的示意 圖。如圖2所示，鏡頭模組30包含具正屈光度的一第一透 鏡群32、具負屈光度的一第二透鏡群34、及具正屈光度 的一第三透鏡群36,第一透鏡群32鄰近放大側，第三透 13 [S] 201209471 鏡群36鄰近縮小側，且第二透鏡群34位於第一透鏡群 32與第三透鏡群36之間。縮小側設置有一影像處理元件 50，且一孔徑光攔28設置於第一透鏡群32與第二透鏡 群34之間。本實施例與圖1的實施例差別在於第二透鏡 群34僅具有單一透鏡M4，從放大側至縮小側依序排列 的第一透鏡Μ卜第二透鏡M2、第三透鏡M3、第四透鏡 Μ4、第五透鏡Μ5、與第六透鏡Μ6的屈光度依序為負、 正、正、負、正、正。再者，為達到廣角化的目的，本 實施例設計使第一透鏡Ml的屈光度為負，且本實施例設 計使第一透鏡Ml朝向放大側的面為凹面，如此可縮小第 一透鏡Ml的尺寸。另外，雖然當第一透鏡mi朝向放大 侧的面為凹面時會造成負向的畸變(distortion)，但可利用 將第五透鏡M5的表面S11形成為非球面的方式來修正。 同樣地，為了修正第一透鏡M1的負屈光度所產生的像 差’第二透鏡M2及第三透鏡M3需有較大的正屈光度， 且為有效減少畸變同時獲得遠心(telecentric)鏡頭系統的 效果’第三透鏡群36的第五透鏡M5與第六透鏡M6的 屈光度均需為正。 如下說明圖2之鏡頭模組30的一透鏡設計實例。需 注忍下述之表三及表四中所列的設計值並非用以限定本 發明’ 何熟習此項技術之人士在參照本發明之後，當 可對其參數或設定作適當更動，惟其仍屬於本發明之範 201209471 缚内。<Table 2> S10 Sll K 0 0 C2= 0 0 C4= -7.65E-03 -2.21E-03 C6= 1.33E-03 3.84E-04 C8= -1.77E-03 -3.74E-04 C10= 5.49E-04 7.85E-05 C12=-8.38E-05 -8.65E-06 FIG. 2 is a schematic diagram of a lens module 30 according to another embodiment of the present invention. As shown in FIG. 2, the lens module 30 includes a first lens group 32 having a positive refracting power, a second lens group 34 having a negative refracting power, and a third lens group 36 having a positive refracting power. The first lens group 32 Adjacent to the magnification side, the third through 13 [S] 201209471 is adjacent to the reduction side, and the second lens group 34 is located between the first lens group 32 and the third lens group 36. An image processing element 50 is disposed on the reduction side, and an aperture stop 28 is disposed between the first lens group 32 and the second lens group 34. The difference between the embodiment and the embodiment of FIG. 1 is that the second lens group 34 has only a single lens M4, and the first lens is sequentially arranged from the magnification side to the reduction side, the second lens M2, the third lens M3, and the fourth lens. The diopter of the fourth lens 5, the fifth lens Μ5, and the sixth lens Μ6 are negative, positive, positive, negative, positive, and positive. Furthermore, in order to achieve the purpose of wide-angle, the embodiment is designed such that the diopter of the first lens M1 is negative, and the embodiment is designed such that the surface of the first lens M1 facing the magnification side is concave, so that the first lens M1 can be reduced. size. Further, although the negative distortion is caused when the surface of the first lens mi toward the enlarged side is concave, it can be corrected by forming the surface S11 of the fifth lens M5 as an aspherical surface. Similarly, in order to correct the aberration generated by the negative refracting power of the first lens M1, the second lens M2 and the third lens M3 need to have a large positive refracting power, and the effect of effectively reducing the distortion while obtaining a telecentric lens system. The diopter of the fifth lens M5 and the sixth lens M6 of the third lens group 36 need to be positive. A lens design example of the lens module 30 of FIG. 2 will be described below. It is to be noted that the design values listed in Tables 3 and 4 below are not intended to limit the invention. Those skilled in the art will be able to make appropriate changes to their parameters or settings after referring to the present invention. It belongs to the scope of the invention 201209471.
<表三> 表面 曲率半徑 (mm) 間距(mm) 折射率 阿貝數 S1 -4.689353 0.75 1.531717 48.84072 S2 15.429133 0.828995 S3 -5.684862 1.470203 1.809979 40.94819 S4 -4.381142 0.1 S5 4.061052 2.238399 1.6779 54.88744 S6 -26.623482 -0.184656 孔徑光 攔(S7) Infinity 0.319376 S8 7.235668 0.915041 1.92286 18.89691 S9 3.338229 7.655171 S10 -20.000000 1.404481 1.53116 56.04383 S11 -6.011043 0.1 S12 -50.000000 2 1.799516 42.22501 S13 -11.153957 0.1 S14 Infinity 0.4 1.508469 61.1878 15 201209471 S15 Infinity 0.306000 IMA Infinity 在表三_中’間距是指兩相鄰表面間於光轴A上之直 線距離’舉例來說，表面S1之間距，即表面S1至表面 S2於光軸A上之直線距離。此外，在表三中，表面S1、 S2為第一透鏡L1的兩表面，表面S3、S4為第二透鏡L2 的兩表面’表面S5、S6為第三透鏡L3的兩表面，表面 S7為孔徑光欄18,表面S8、S9為第四透鏡L4的兩表面， 表面S10、S11為第五透鏡L5的兩表面，表面S12、S13 為第六透鏡L6的兩表面，且表面S14、S15為一用於影 像處理元件5〇之玻璃蓋(cover glass) 42的兩表面，再者， 於本實施例中’例如第二透鏡M2、第三透鏡M3及第五 透鏡M5為非球面鏡片，即表面S3、S4、S5、S6、S10、 S11可為非球面，而非球面的公式如下： Z(h)=Wr^?Tk)hv + C2h2+oh4+Ceh6+Csh8+Cloh，°+Ci2h，2 於上式中’z為光轴方向之偏移量’h為非球面距光軸 的垂直高度，Γ為接近光軸處的曲率半徑，k是二次曲面常 數’而C2-Ci2為非球面高次項係數。表面S3、S4、S5、S6、 S10、S11的非球面係數及k值如表四所示： [S] 16 201209471 <表四〉 S3 S4 S5 S6 S10 Sll K 0 0 0 0 19.015831 -9.757112 C2= 0 0 0 0 0 0 C4= 5.03E-03 1.88E-03 -3.44E-03 -2.79E-03 -4.87E-04 -6.74E-04 C6= -5.61E-04 -7.85E-05 -3.99E-05 1.41E-04 -4.16E-05 -1.84E-05 C8= 8.61E-05 3.64E-05 1.21E-05 3.85E-06 6.38E-07 3.15E-07 C10= -2.19E-06 -2.35E-06 -2.10E-06 -1.29E-06 3.32E-07 3.27E-08 C12= -3.62E-08 1.74E-07 9.21E-08 8.79E-08 -4.22E-09 4.92E-09<Table 3> Surface Curvature Radius (mm) Spacing (mm) Refractive index Abbe number S1 -4.689353 0.75 1.531717 48.84072 S2 15.429133 0.828995 S3 -5.684862 1.470203 1.809979 40.94819 S4 -4.381142 0.1 S5 4.061052 2.238399 1.6779 54.88744 S6 -26.623482 -0.184656 Aperture stop (S7) Infinity 0.319376 S8 7.235668 0.915041 1.92286 18.89691 S9 3.338229 7.655171 S10 -20.000000 1.404481 1.53116 56.04383 S11 -6.011043 0.1 S12 -50.000000 2 1.799516 42.22501 S13 -11.153957 0.1 S14 Infinity 0.4 1.508469 61.1878 15 201209471 S15 Infinity 0.306000 IMA Infinity The three-medium spacing refers to the linear distance between two adjacent surfaces on the optical axis A. For example, the distance between the surfaces S1, that is, the linear distance from the surface S1 to the surface S2 on the optical axis A. Further, in Table 3, the surfaces S1, S2 are the both surfaces of the first lens L1, the surfaces S3, S4 are the two surfaces of the second lens L2, and the surfaces S5, S6 are the surfaces of the third lens L3, and the surface S7 is the aperture The light bar 18, the surfaces S8, S9 are the two surfaces of the fourth lens L4, the surfaces S10, S11 are the two surfaces of the fifth lens L5, the surfaces S12, S13 are the two surfaces of the sixth lens L6, and the surfaces S14, S15 are one The two surfaces of the cover glass 42 for the image processing element 5, and further, in the present embodiment, for example, the second lens M2, the third lens M3, and the fifth lens M5 are aspherical lenses, that is, surfaces. S3, S4, S5, S6, S10, S11 can be aspherical, and the formula of the non-spherical surface is as follows: Z(h)=Wr^?Tk)hv + C2h2+oh4+Ceh6+Csh8+Cloh,°+Ci2h,2 In the above formula, 'z is the offset of the optical axis direction'h is the vertical height of the aspherical surface from the optical axis, Γ is the radius of curvature near the optical axis, k is the quadratic constant ' and C2-Ci2 is aspherical High order coefficient. The aspherical coefficients and k values of the surfaces S3, S4, S5, S6, S10, and S11 are as shown in Table 4: [S] 16 201209471 <Table 4> S3 S4 S5 S6 S10 Sll K 0 0 0 0 19.015831 -9.757112 C2 = 0 0 0 0 0 0 C4= 5.03E-03 1.88E-03 -3.44E-03 -2.79E-03 -4.87E-04 -6.74E-04 C6= -5.61E-04 -7.85E-05 - 3.99E-05 1.41E-04 -4.16E-05 -1.84E-05 C8= 8.61E-05 3.64E-05 1.21E-05 3.85E-06 6.38E-07 3.15E-07 C10= -2.19E- 06 -2.35E-06 -2.10E-06 -1.29E-06 3.32E-07 3.27E-08 C12= -3.62E-08 1.74E-07 9.21E-08 8.79E-08 -4.22E-09 4.92E -09
於一實施例中，為了達到較佳的成像品質，當第一 透鏡構成該第一透鏡群的一第一子群，該第二透鏡連同 該第三透鏡構成該第一透鏡群的一第二子群，鏡頭模組 之有效焦距為f，且第二子群的有效焦距為fSG2時，鏡頭模 組滿足下列條件： 0.2<fSG2/f<0.5。 若(fSG2/f)小於0.2，則球差和彗差等像差會變大，若 (fSG2/f)大於〇.5，則不足以修正第一子群造成的像差，且 [S] 17 201209471 第二子群的屈光度變小易使鏡頭系統的長度增加。 於一實施例中，當鏡頭模組之有效焦距為f,第二透 鏡群的有效焦距為fG2時，鏡頭模組滿足下列條件·· 〇.6< 丨 fG2 丨 / f< 1.5。 若（I fc2丨/f)之值滿足上述條件，則對離轴像差特別 是場曲和S差有較好的修正。若（丨fG2丨/f)小於G 6，雖然 鏡頭系統可以驗尺寸，但會產生較大的像差且較難修 正離軸像差，反之若（i fG2 ! /f)大於i 5，第二透鏡群的屈 光度不足以修正像差。 於一實施例中，當第三透鏡的阿貝數為，第四透 鏡的阿貝數為]> 4時，鏡頭模組滿足下列條件： 20<ι^3 — ι;4<37° 若（Ρ 3 — 4)小於20,兩鏡片的阿貝數過於接近而難 以修正橫向色差，若卜3— 1； 4)大於37則難以修正縱向色 差。 於一實施例中’鏡頭模組之有效焦距為f，第二透鏡 群最靠近縮小侧的透鏡表面的中心至第三透鏡群最靠近 放大侧的透鏡表面的中心的距離為Lg2_G3,則鏡頭模紐滿 足下列條件： 0.4 < L〇2-G3/ f < 1 〇 201209471 若(LG2-G3/f)小於〇·4，則第二透鏡群至第三透鏡群的 距離會太小而不足以放置投影系統所需的元件，若 (LG2-G3/ f)大於1會使第二透鏡群的屈光度變小而不足以 修正其他鏡片造成的像差。 於一實施例中’為達到一遠心系統的目的，所以第 三透鏡群均為正透鏡，當鏡頭模組之有效焦距為f，第三 透鏡群的有效焦距為fG3，該鏡頭模組滿足下列條件： 0.6 < f*G3/ f < 2。 若（fGs/f)大於2，則第三透鏡群的屈光度不足以使鏡 頭成為一遠心系統’若(fG3/f)小於0.6，則第三透鏡群的 屈光度過大’使得第二透鏡群至第三透 鏡群的距離LG2_G3*小而不足以放置投影系統所需的元 件。 因此，藉由上述各個實施例之設計，鏡頭模組具有 如下全部或至少其一之優點： (1) 低橫向色差； (2) 低畸變像差； (3) 大視場角； (4) 低遠心角’可控制在3.1度内；及 201209471 (5)僅使用6片鏡片即可達到修正像差的目的。 圖3至圖5為本發明的鏡頭模組的光學數據模擬圖。 圖3為光學調變傳遞函數(modulation transfer function ; MTF)曲線圖’其橫軸為以線對數/毫米表示的空間頻率 (spatial frequency in cycles per millimeter )’ 縱軸為光學 轉移函數的模數（modulusoftheOTF)。圖4為場曲（field curvature)圖和畸變(distortion)圖，其中場曲圖的橫軸代表 與焦面相距的距離，縱軸代表從〇到最大的場；畸變圖的 才κ轴代表畸變百分比，縱軸代表從〇到最大的場。圖5為 一松向色差圖。由圖3至圖5可清楚看出本發明的鏡頭模 組具有良好的成像品質。 惟以上所述者’僅為本發明之較佳實施例而已，當不能 以此限林發明實施之綱，g卩大凡依本發财請專利範圍 及發明說_容所作之簡單的等效變化與修飾，皆仍屬本發 明專利涵蓋之範圍内。另外，本發明的任一實施例或申請 專利範圍㈣達成本發明所揭露之全部目的或優點或特 點。此外’摘要部分和標題僅是时伽專利文件搜尋 之用，並非用來限制本發明之權利範圍。 [S] 20 201209471 【圖式簡單說明】 圖1為依本發明一實施例之鏡頭模組的示意圖。 圖2為依本發明另一實施例之鏡頭模組的示意圖。 圖3至圖5為本發明的鏡頭模組的光學數據模擬圖。 【主要元件符號說明】 10、30 鏡頭模組 L1-L7、M1-M6 透鏡 12、32 第一透鏡群 S1-S17 表面 14、34 第二透鏡群 A光轴 16、36 第三透鏡群 LG2_G3第二透鏡群與第三 18 ' 28 孔徑光攔 透鏡群距離 22、42 玻璃蓋 40、50 影像處理元件In an embodiment, in order to achieve better imaging quality, when the first lens constitutes a first subgroup of the first lens group, the second lens together with the third lens constitutes a second of the first lens group. Subgroup, the effective focal length of the lens module is f, and the effective focal length of the second subgroup is fSG2, the lens module satisfies the following conditions: 0.2 < fSG2 / f < 0.5. If (fSG2/f) is less than 0.2, the aberrations such as spherical aberration and coma will become large. If (fSG2/f) is larger than 〇.5, it is not sufficient to correct the aberration caused by the first subgroup, and [S] 17 201209471 The diopter of the second subgroup becomes smaller, which increases the length of the lens system. In one embodiment, when the effective focal length of the lens module is f and the effective focal length of the second lens group is fG2, the lens module satisfies the following conditions: 〇.6< 丨 fG2 丨 / f< 1.5. If the value of (I fc2 丨 / f) satisfies the above conditions, there is a good correction for off-axis aberrations, especially field curvature and s difference. If (丨fG2丨/f) is smaller than G 6, although the lens system can measure the size, it will produce large aberrations and it is difficult to correct the off-axis aberration, and if (i fG2 ! /f) is greater than i 5, the first The diopter of the two lens groups is not sufficient to correct the aberration. In one embodiment, when the Abbe number of the third lens is 4 and the Abbe number of the fourth lens is 4>, the lens module satisfies the following conditions: 20<ι^3 — ι; 4<37° (Ρ 3 — 4) is less than 20, the Abbe number of the two lenses is too close to be difficult to correct the lateral chromatic aberration, and if the 1-3 is greater than 37, it is difficult to correct the longitudinal chromatic aberration. In one embodiment, the effective focal length of the lens module is f, the distance from the center of the lens surface closest to the reduction side of the second lens group to the center of the lens surface closest to the magnification side of the third lens group is Lg2_G3, and the lens mode is Newton satisfies the following conditions: 0.4 < L〇2-G3/ f < 1 〇201209471 If (LG2-G3/f) is less than 〇·4, the distance from the second lens group to the third lens group will be too small and insufficient In order to place the components required for the projection system, if (LG2-G3/f) is greater than 1, the diopter of the second lens group becomes small enough to correct the aberration caused by the other lenses. In an embodiment, in order to achieve the purpose of a telecentric system, the third lens group is a positive lens. When the effective focal length of the lens module is f and the effective focal length of the third lens group is fG3, the lens module satisfies the following Condition: 0.6 < f*G3/ f < 2. If (fGs/f) is greater than 2, the diopter of the third lens group is insufficient to make the lens a telecentric system. If (fG3/f) is less than 0.6, the diopter of the third lens group is too large, so that the second lens group is The distance of the three lens group LG2_G3* is small enough to place the components required for the projection system. Therefore, with the design of each of the above embodiments, the lens module has all or at least one of the following advantages: (1) low lateral chromatic aberration; (2) low distortion aberration; (3) large angle of view; (4) The low telecentric angle can be controlled within 3.1 degrees; and 201209471 (5) The correction aberration can be achieved by using only 6 lenses. 3 to 5 are optical data simulation diagrams of the lens module of the present invention. Figure 3 is a modulation transfer function (MTF) graph whose horizontal axis is the spatial frequency in cycles per millimeter'. The vertical axis is the modulus of the optical transfer function ( modulusoftheOTF). Figure 4 is a field curvature diagram and a distortion diagram, in which the horizontal axis of the field curvature map represents the distance from the focal plane, the vertical axis represents the field from the 〇 to the maximum; the κ axis of the distortion map represents the distortion. Percentage, the vertical axis represents the field from 〇 to the largest. Figure 5 is a loose chromatic aberration diagram. It is apparent from Figs. 3 to 5 that the lens module of the present invention has good image quality. However, the above description is only a preferred embodiment of the present invention. When it is not possible to implement the invention in this way, the simple equivalent change made by the patent scope and the invention. And modifications are still within the scope of the invention patent. In addition, all of the embodiments or the scope of the invention (4) of the present invention achieve all of the objects or advantages or features of the present invention. In addition, the 'summary section' and the headings are only used for the search of the gamma patent documents and are not intended to limit the scope of the invention. [S] 20 201209471 [Simplified Schematic] FIG. 1 is a schematic diagram of a lens module according to an embodiment of the present invention. 2 is a schematic diagram of a lens module according to another embodiment of the present invention. 3 to 5 are optical data simulation diagrams of the lens module of the present invention. [Major component symbol description] 10, 30 lens module L1-L7, M1-M6 lens 12, 32 first lens group S1-S17 surface 14, 34 second lens group A optical axis 16, 36 third lens group LG2_G3 Two lens groups and the third 18' 28 aperture optical lens group distance 22, 42 glass cover 40, 50 image processing components